Berlocq cruised to 6-2, 6-1 victory over Russian Andrey Kuznetsov on the clay courts of Vina del Mar, joining Frenchman Guillaume Rufin, 16-year-old Chilean wild card Christian Garin and Argentine Horacio Zeballos among the Day 2 winners.
Also recording a first-round victory Tuesday was 2011 winner Tommy Robredo, who dispatched fellow Spaniard Pere Riba 6-2, 6-2.
Nadal, who has been out of action with a knee injury since June, returned to the court in a doubles match with teammate and defending Vina del Mar champion Juan Monaco.
They bested the duo of Frantisek Cermak and Lukas Dlouhy 6-3, 6-2.
Nadal had a first-round bye in the single competition. He was set to take on qualifier Federico Delbonis Wednesday.
Texas principal bans speaking Spanish, stirs controversy
Man spent 15 hours in jail for plugging electric car into an outlet at a school